This invention relates to pulse generator circuits and more particularly to multivibrator circuits for producing constant width output pulses in response to applied alternating input signals.
In a control system it is quite often desired to generate a constant width pulse in response to an applied alternating input signal. For instance, it might be desired to provide a precision one shot function where, in response to either the positive or negative going transition of the applied input alternating signal, a constant width output pulse is generated. The output pulse can then be integrated to provide an analog voltage. This analog voltage may be used to control or adjust some parameters of the system in which the multivibrator circuit is utilized. Moreover, it might be desired to generate a doubling one shot function wherein fixed output pulses are generated at both the negative and the positive going transitions of the applied alternating input signal.
It is important in such pulse generating systems that the output pulses be generated for the particular transition of the applied alternating input signal. A problem can occur when the frequency of the input alternating input signal is increased such that the period becomes quite small. In this mode it is quite possible that in prior art circuits the generation of the pulses will occur very rapidly, becoming crowded, such that the pulses tend to crowd together to become one and are no longer distinct from one another. If this were to happen, and if the pulses were integrated in the system, then an analog voltage having an incorrect magnitude could be generated. Thus it is important that crowding of the pulses be prevented during high frequency modes of operation of the control circuit.